Model trains have been around since the dawn of railroading itself. Early model and toy trains predate the availability of electricity, and were often powered by a clockwork mechanism. O Scale was one of the first sizes of model trains; John Gwartzell was building O Scale trains as early as 1894. Commercial manufacturing of O Scale equipment began in the 1910s, and O Scale, originally called Gauge 0 (zero) in Europe, was the predominant scale from the early 1930s until after World War II.

In the United States, O Scale 2-Rail (OS2R) history starts with pre-World War I tinplate toy trains. These toy trains used 3-Rail track spaced 2 1/8” apart, and were manufactured in the United States by the

Ives Company in 1910. They were followed by Lionel and A. C. Gilbert (American Flyer), among others. These trains ran on a track called “Standard Gauge.” Note: this “Standard Gauge” is different than “Standard Gauge (OW5)” in O Scale. The “Standard Gauge” introduced in 1906 by Lionel was not a scale, but rather a track width at 2 1/8”. The trains that run on this track were handsome, but the sizes of the trains that ran on this track varied, and were often shorter than their scale model counterparts. These were the first toy trains to run on electricity. These companies soon offered smaller sizes of toy train, including O Scale (1/48” to the foot, or 1:48 scale) and  S Scale (3/16” to the foot, or 1:64 scale).

These early trains were toys. Most tinplate locomotives and rolling stock were caricatures of real trains in both appearance or dimensions. Later, however, companies started producing models that were more realistic looking and followed prototype dimensions more closely. In the late 1930s, Lionel produced a line of locomotives and cars that was true to 1/4″ O Scale right down to the wheels, although they still ran on 3-Rail track. The introduction of such models was a boon to O Scale modelers seeking more prototypical appearances, who could now modify these models, if necessary, to run on their own 2-Rail track. Many took this route because in the early days of O Scale, commercially available models and supplies were limited, so if a person wanted a particular model, it would be necessary to build it from scratch, provided they had the proper tools, including machine tools, and the know-how to do so.

Many of the early O Scale 2-Rail layouts used 2-Rail track with an outside rail added on one side of the two running rails. This outside third rail carried one side of the power to the trains and was mounted on raised insulators. The track looked much like the track of prototype electrified railroads that do not use an overhead wire system for power distribution. Power pickup from this outside rail was by DC current sliding shoes mounted on the powered units. The more realistic standard of 2-Rail operation did not become widespread until the 1940s.

Like everything in which a broader interest grows, accessibility to desired models required that they be more readily available. From the mid-1930s on, commercially produced models appeared on the market. Modelers had a continually larger basket of models and detail parts to choose from. Early kits were mostly craftsman-type kits which required work and time to build. Car kits were composed of wood and/or metal parts. Locomotives were available as castings kits, machined kits, or fully assembled and were priced accordingly. Even some of the easier-to-build kits required some drilling as well as tapping for screws. By the late 1930s, O Scale was the dominant size for scale railroad models, with a large variety of equipment being offered.

Better known O Scale manufacturers of those years included Lobaugh, Scale-Craft, Scale Model Railways, Ferris, Walthers, Auel, Egolf, Lenoir, Icken, Saginaw, Edwin Alexander, Westbrook, Staples, and Rail Craft. A number of these companies converted to military production during World War II, and did not return to model train production after the war. Others failed to make the switch to injection-molded plastic models, or otherwise failed to keep pace. Fortunately, new companies arrived (Max Gray, Kemtron, and later Atlas, MTH, Sunset/3rd Rail, Intermountain, Red Caboose, Weaver) to replace the old ones and made names for themselves.

After the end of World War II, HO Scale gained popularity amongst modelers. Soon O Scale was no longer the majority scale. The smaller scale (3.5mm to the foot) fit well in smaller houses then being built. New HO manufacturers developed injection-molded plastic models, making it easier and cheaper to get started. Beginning in 1952, however, a new phase began for OS2R with the introduction of highly-detailed built-up O Scale brass locomotives and cars that were imported from Japan and South Korea. Imports of these brass models continue to this day by various companies, with models getting even more detailed and elaborate, including factory-painted models, although most models are now made in South Korea with some manufacturing being done in mainland China in recent years.

An increasing number of rather inexpensive plastic models with details rivaling more expensive brass models have come on the market. These include built-up plastic models that are ready to run right out of the box: no assembly or painting required. You can get a model railroad running immediately without much wait or work. Another trend is that more manufacturers are producing assembled track sections so that modelers who do not want to hand lay track can build their layouts more quickly and easily.

Manufacturers of 3-Rail equipment, including MTH, K-Line, Lionel, Williams, Weaver and Atlas have improved the quality and fidelity of their models. Some cars are offered in 2-Rail versions, or in 3-Rail versions with features that allow the modeler to easily convert it to 2-Rail.

OS2R has an international following. While the core scale in America is 1:48, British and Australian OS2R models are built to 1:43.5. Continental European OS2R models are built to 1:45. In the earlier days of the scale, some American models were built to 17/64th scale to square with the slightly out of gauge track (the gauge itself being derived from British O Scale). All of the trains built to these scales run on track that is 1 1/4” wide. To find out more about the various track gauges you can model in OS2R, please visit OS2R Track Gauges.

This article is meant as an overview of OS2R history. If you are interested in learning more about the early history of O Scale or model railroading in general, we suggest looking for magazine articles on specific historical topics, such as the “O Scale Archeology” column in O Scale Trains Magazine. Books such as 150 Years of Train Models by Harold Carstens or early issues of magazines such as Model Railroader, Model Craftsman (now known as Railroad Model Craftsman), and Miniature Railroading are also recommended. The first two magazines have been in publication since the 1930s (the last one ceased publication a long time ago). There were also two magazines devoted exclusively to O Scale in the early 1950s called The Whistle Stop and The O Gauger, but they are hard to find. Information can also be found in early issues of the NMRA Bulletin (White River Press), American O Scale 1927-1965 and A Guide to Modern O Scale, Second Edition (2009) by O Scale Trains Magazine.